1 A View on the Global Expansion of Wireless Internet Reed Burkhart Walnut Creek, USA 1. ABSTRACT The value of the Internet is its expansive, all encompassing, reach which is extended further by wireless systems. Wireless's advantages in mobility, broadcast, and remoteness have important implications for new Internet architectures involving satellites, terrestrial cellular, point-to-point, and point-to-multipoint wireless technologies at various radio frequencies and also micrometer (laser) wavelengths. Regulators, service providers, and technology developers must leverage these strengths to develop new wireless-hybrid Internet architectures that meet user demands and match user demand densities. 2. CONTENTS. This paper includes the following sections: 1. Abstract 2. Contents 3. Why Wireless 4. Integration Issues: Wireless & Internet 5. Markets and Applications 6. Demand Density 7. Conclusion 3. WHY WIRELESS. The recent rapid growth in wireless communication follows trends toward higher mobile data rates, mobile services integration, broadcast-internet convergence, and Internet expansion leveraging wireless's strengths in mobility, broadcast, and remoteness. The need for anytime, anywhere communications, the Internet's exponentially increasing influence from Metcalfe's Law, and Moore's Law advancements in electronics provide many new opportunities for wireless architectures and applications of wireless. The greatest opportunities for wireless Internet extensions will match the mobility, broadcast, and remote strengths of wireless. These strengths become increasingly complementary to the wired Internet: as Internet applications extend to specialized areas (such as mobilization of Internet data to improve transportation, sales, or other mobile business processes), as popular and high-value content is multicast over wireless broadcast channels to bypass network congestion, and, when wired Internet connections simply are not available. In order to achieve the benefits of wireless Internet, the diverse and sometimes proprietary architectures of wireless networks must be harmonized with Internet standards. 4. INTEGRATION ISSUES: WIRELESS & INTERNET. The major wireless applications have historically been persistent, or streaming, demanding continuous bandwidth and employing fixed-length packets (examples: cellular voice, broadcast video). Streaming applications naturally suit the persistence of point-to-point or broadcast communication links. Since wireless spectrum is such a precious commodity, bursty data traffic that
2 inefficiently uses wireless bandwidth has been far less common. In contrast, the Internet's original purpose was to connect computers to enable the sharing of bursty data encapsulated in variable-length packets over a distributed robust architecture. The empowering Internet architecture is based on a web of alternate routes yielding an entire web of point-to-point links (each, individually capable of persistence and continuity) to support a variety of indeterminate (often bursty) computer traffic. Bursty and indeterminate data traffic is difficult to package efficiently for transmission. One of the strengths of the Internet is its ability to provide economies of scale and sharing for the transmission of bursty data (although streaming media is far less natural to accommodate). Performance of the Internet depends on the performance of each transmission segment used for any particular transmission. High demand routes are supported by plenty of bandwidth using high-capacity, WDM fiber links. But in the many lesser-traveled parts of the Internet where demand disperses (last & first miles, etc.), the infrastructure is less mature. These lower density routes are good candidates for wireless links, at least as an interim solution. As the Internet is re-engineered to accommodate voice and video, the Internet will continue to grow to include hybrid protocols and architectures, including wireless transport as appropriate. An example is the TCP-SAT working group of the IETF (Internet Engineering Task Force), investigating suitable adaptations of the TCP protocol (that vies for reliability in Internet transmissions) for satellite links, such as removing slow start, and lengthening acknowledgment periods that otherwise limit the bandwidth of Internet over satellite. As wireless systems are re-engineered to accommodate Internet applications and bursty data traffic, wireless systems will evolve to include hybrid protocols and architectures that can better accommodate a mixture of bursty and streaming IP traffic. Examples are the IEEE wireless LAN standard for peer-to-peer short-range connectivity in the Mbps bit rate range (IEEE b, or High Rate, will extend IEEE to 11 Mbps), and wireless ATM standardization activities for broadband local telephony and Internet access. 5. MARKETS AND APPLICATIONS. The Internet market is so broad that it defies any succinct description, but at least includes: communications computing multimedia entertainment publishing retail gaming automation commerce education, and government The pervasive impact of the wired Internet has become increasingly obvious. The growing presence of the wired Internet has alerted wireless manufacturers, service providers, and users of the expanding opportunities for wireless data internetworking. As the browser graphical user interface (Mosaic, Netscape, Internet Explorer) was key to popularizing and defining the wired Internet, what wireless Internet element will be similarly defining?
3 Future Mobility In mobility applications, laptops can use established human interfaces like browsers and mousepads, but other prospective wireless Internet terminals (cell phones, pagers, and PDAs) must accommodate their smaller form factor leading to developments such as the Wireless Applications Protocol (WAP i ), Wireless Markup Language (WML), and several proprietary wireless protocols (Phone.com ii, or Symbian's EPOC iii ). Strong growth is anticipated in the market for Internet cell phones and PDAs. Future Broadcast In broadcast applications (that aren't mobile), a computer or set top box is the typical destination; hence much interest lies in the home or business platform for reception of broadcast Internet, digital video, and audio content. Systems such as WebTV, TiVo, Replay, Wink, OpenTV and MediaHighway all are vying for mindshare in the broadcast wireless Internet arena. Wired cable television broadcast and DSL technologies and services are also largely shaping this area. Similar to a satellite s ability to reach an entire third of the planet Earth, the Internet provides access to the current 4% of the world online population (which affluent fraction controls a far greater fraction of world buying power). The terrestrial Internet provides a far less direct path to that 4% than satellites assuming that computers are integrated as supplementary broadcast receivers. An early 1999, Xerox study found that 5% of Internet websites get 74.81% of Internet traffic. This convergence of users on a small fraction of destinations indicates that it may be possible to multicast via satellite a very interesting subset of Internet content for high speed anytime access from local storage. Future Remote In remote applications (that aren't mobile or broadcast), there is a large and growing segment of wireless Internet that uses wireless point-to-point transport to extend the Internet, involving minimal changes to current transport systems (an exception is satellite transmissions, where delay and TCP require accommodations). Projections from Pioneer Consulting for last mile (remote) access technologies (wireless and wireline) show satellite and LMDS capturing a significant share of the Internet access market (Figure 1, High Speed Broadband Access Forecasts) behind DSL and cable modems. Making such projections is fraught with challenges, for example estimating infrastructure costs for unbuilt, yet-to-bedesigned systems. Other wireless Internet applications are remote in other ways: a room in a house may be remote from another as far as wires are concerned. This remote issue has led to standardization efforts in home networking such as the Home RF Working Group iv. IEEE promises to be a widely adopted indoor wireless communications standard. New work on wireless personal networks (IEEE ) has begun that promise to further empower individuals with information via electronic organizers or wearable computers. Wireless laser communication systems offer very high speeds (successful tests have been conducted at up to 2.5 Gbps) with line of sight propagation. Although susceptibility to optical outage from fog and rain would usually mandate a wireless or wired backup, the ability to install super-high-speed links quickly is unique to the domain of free-space laser communications. Free-space lasers promise to mirror the high-capacities available via fiber-optic cables.
4 Of all the wireless Internet applications, which are most interesting from an economic point of view? Figure 2, Wireless Tools Suit the Geography, shows a variety of current and planned wireless systems according to bit rate and coverage range. The fundamental economics are apparent. Small, relatively low power, highly portable devices like pagers and cell phones are economically suited to cell sizes ranging from 100m to several kilometers, according to demand densities. But broadcasts to an entire continent or wireless intercontinental links require global wireless devices on the scale of satellites. Of course, services that are most unique (fewest prospective competitors) have the best chance of establishing profitable and defensible franchises. Figure 2, Wireless Tools Suit the Geography, shows the hot spots of competition to be in the area of mobile voice with growing activity in the area of short range fixed high-speed wireless devices (wireless LANs, Bluetooth, HiperLAN-2). Wireless Internet broadcast is also expected to enjoy heightened market activity, whether to cell phones, pagers, homes or businesses. From the device manufacturer's perspective, (Figure 3, Terminals: matching demands of wireless Internet?) the most numerous prospective wireless Internet device is the TV set, followed by cell phones, personal computers, pagers, PDAs, and specialized mobile radios. Cellular wireless Internet technology vendors promote the idea that cell phones could supersede personal computers as the predominant device for Internet access since there are more cell phones than personal computers, and cell phones are more frequently at hand. This assumes that cell phones are a satisfactory interface for a majority of Internet activities, which is far from certain (imagine typing an note on your cell phone). Current Mobility As for current wireless system statistics, the reality of wireless mobile data applications today is in proprietary systems with little market penetration (Figure 4, Wireless Data is a Recent Trend). Hambrecht & Quist recently projected the value of mobility in 2004 to remain mainly with voice applications with a growing component in web, , data, and push services (Figure 5, Value of Mobility 2004). Current Broadcast and Remote Broadcast Internet markets are similarly new, with few collected statistics. Recent research from DTT Consulting contrasts the second two wireless strengths, broadcast and remoteness, in the case of satellite Internet markets (Figure 6, Satellite Internet Growth) showing a market of about US$ 0.25 Billion in 1999, 99.4% of which is remote (both access and trunking) and 0.6% of which is broadcast Internet (such as ibeam v and SkyCache vi ). 6. DEMAND DENSITY Demand density is a measure of the geographical concentration of demand. It may be measured over a continent, a country, a satellite spot beam, a metropolitan area, a GSM cell, a square kilometer, a floor of an office building, a home, or an individual carrying multiple wireless devices. When users are concentrated, the cost of serving them is lower in either the wired or wireless case. With concentration of demand come higher traffic volumes for which high capacity wireline systems are particularly well suited. Therefore, except for mobility applications or remote urban scenarios (e.g., nearby locations rendered remote by rivers or freeways) higher density areas generally favor wired solutions. Internet user distribution follows population distribution and wealth distribution. Figure 7,
5 Worldwide Population Density Map, shows worldwide population density. 73.4% of earth is water or arctic region, 60% of land is not populated (mountains or deserts), 50% of population is in cities, 83% of users occupy only 5% of the earth. Urban markets are the focus of wired technologies, and also wireless mobility and broadcast technologies. Yet wireless remote (wired-alternative) technologies such as wireless local loop find their best market in suburban and rural markets. Satellite wireless broadcasts suit urban and rural alike, but multibeam wireless-remote satellite systems have the result of increasing capacity in rural areas at the expensive of peak capacity to urban areas. The challenge of architecting a satellite system with spot beams (usually uniformly distributed in the coverage area) that matches well the demand distribution is a major factor in developing a competitive broadband satellite architecture. It is worth emphasizing that multibeam systems do not leverage satellites' single most unique attribute: reaching an entire continent with a single transmission. The challenge of getting a new satellite architecture right years in advance (required for design and construction) are immense, pointing towards a system with as diverse a set of auspicious applications as possible. In spite of such challenges, satellites are singular in their potential for ubiquitous high-speed communications due to their unparalleled reach. Figure 8, Worldwide Satellite ISP Links, shows that satellite Internet backbone links are predominantly to countries with less demand density (source DTT Consulting), as undersea cables have already linked countries with the highest demand densities. Figures 9 and 10 show the distribution of population density for a worldwide crosssection of 40 countries both unweighted and weighted with GNP. Sources include: CIA World Factbook for land area, CIBC for GNP figures, and United Nations Environment Programme for population density data. Wireless and wired systems each have profitability thresholds for demand density useful to consider when evaluating most effective alternatives. It is useful to differentiate between cost to pass a prospective user and the cost to serve a prospective user. The cost to pass users and to serve users is different if additional equipment is needed to serve, and it usually is for both wireless and wired networks. In the case of wireless networks the difference can be substantial since wireless systems can be designed for very low initial penetration. 8. CONCLUSION. In late 1997 the ITU predicted five possible eventualities for the Internet: 1. Business as usual 2. Splinter-nets (controlled by ISPs) with limited cross interoperability 3. Hypergrowth-incited meltdown 4. Convergence with conventional public networks 5. Birth of a new alternative infrastructure In fact, all 5 alternatives can and have begun to coexist. Business as usual is a bit of an oxymoron since the only thing usual about the Internet is change. Still, linking islands in the pacific would not have been business-asusual without wireless. Proprietary networks have been established, typically with broad interoperability, but creating higher performance levels for those able to pay to be on the superior platform. Most wireless networks are proprietary, and
6 interoperability is one of the issues to be overcome. Meltdown has occurred on occasion with major high-profile online companies. A recent Wall Street Journal article vii estimates the use of satellites will help overcome backbone congestion by multicasting to the edge of the network. There is an ongoing convergence of Internet with conventional PSTN, cable TV networks, satellite broadcast networks, cellular networks, and other wired and wireless networks (DSL Internet access over the PSTN, cable modem access, etc.). And, new alternative infrastructures are being developed, notably hybrid wireless-wired networks leveraging the advantageous attributes of wireless systems for mobility, broadcast and remoteness; and matching supply density to demand density. The issues discussed in this paper are worthy of careful consideration when adapting existing wireless infrastructures or when choosing next generation wireless Internet infrastructures and protocols. i Wireless Applications Protocol Forum, or WAP Forum, ii Phone.com, iii Symbian, iv Home RF Working Group, v ibeam Broadcasting, vi SkyCache, vii ibeam 's Desnoes Is Betting on Use of Satellites To Transmit Audio and Video Over the Internet, Wall Street Journal, October 21, 1999, page B14.
7 Figure 1. High Speed Broadband Access Forecasts LMDS Satellite Cable XDSL
8 Figure 2. Wireless Systems by Range and Rate 1 Gbps 100 Mbps 10 Mbps 1 Mbps 100 kbps 10 kbps 1 kbps Mobile HiperLAN2 IEEE b Home RF IEEE G Bluetooth IrDA Fixed Free-space LASER MetricomGPRS LMDS High altitude F-GEOS Microwave platforms (NewSkies) Radio F-LEOS (Teledesic) EDGE TETRA DECT ARDIS IS-95 & GSM paging SMS Broadcast M-GEOS (MSAT) M-LEOS (Globalstar) 10 m 100 m 1 km 10 km 10K km 100K km
9 Figure 3. Terminals: Matching Demands for Wireless Internet? 1.4 B television sets MOBILE BROADCAST REMOTE MOBILE & BROADCAST 450 M cell phones 350 M personal computers 125 M pagers
10 Figure 4. Wireless Data is a Recent Trend Source: Wireless Data Handbook, DeRose 1999 subs (K) Geonet CDPD Ricochet SkyTel BSWD ARDIS Teletrac SMRS
11 Figure 5. Value of Mobility 2% - High-speed data / video telephony 5% - Web services 13% - / messaging / push services 80% - Telephony Source: H & Q estimates (10/99) Figure 6. Satellite Internet Growth Access Access 53% growth Multicast 200% growth Backbone $109mm $269mm Backbone 1998 Source: DTT Consulting 1999
12 Figure 7. Worldwide Population Density Map Figure 8. Worldwide Satellite ISP Backbone Links Australasia 10% Intra- American 3% Western Europe 13% Asia 16% Total CEE and CIS 19% Middle East 9% Africa 7% Latin America 23%
13 4500 Figure 9. Population Density Histogram by GNP Range No. of 1-degree Square Regions $30,000 to $35,000 $25,000 to 30,000 $20,000 to 25,000 $15,000-20,000 $10,000 to 15,000 $5,000 to 10,000 <$5, ,000 10, ,000 Hab per Sq Km
14 Fig 10. No. of 1-degree Square Regions X GNP Factor GNP-Scaled Population Density Histogram by GNP Range 0 Example wireless demand density threshold Example wired demand density threshold ,000 10, ,000 Wireless advantage Hab per Sq Km